The Super Hero ID will identify you as a superhero in Super Power Island and tracks the number of villains that you have defeated. With this you can start your mission in getting the other items in Super Power Island.
How to get the Super Hero ID
Go to the Masks and Capes shop then talk to the guy to the left holding the scissors. He will give you a Super Hero ID card which identifies you as a superhero and tracks the number of villains that you have defeated. On the other side of the shop is a row of mannequins that have different costumes on them. Click on them to pick your costume. You can mix and match pieces from all the different costumes.